diff --git a/.changeset/fix-3121-gsd-tools-commands-verb.md b/.changeset/fix-3121-gsd-tools-commands-verb.md
new file mode 100644
index 000000000..9f5f9d740
--- /dev/null
+++ b/.changeset/fix-3121-gsd-tools-commands-verb.md
@@ -0,0 +1,5 @@
+---
+type: Fixed
+pr: 3121
+---
+**`gsd-sdk query commands` no longer returns "Unknown command"** — `commands` was referenced in `references/workstream-flag.md` and by agent tooling for verb discovery but had no SDK handler. A new `commandsList` handler in the native registry returns a sorted JSON array of all registered verb strings. `check.decision-coverage-plan` and `check.decision-coverage-verify` were already registered in the SDK native registry; the remaining gap was the `commands` introspection verb. Closes #3121.
diff --git a/sdk/src/golden/golden-policy.ts b/sdk/src/golden/golden-policy.ts
index 1c3f15445..8a1432771 100644
--- a/sdk/src/golden/golden-policy.ts
+++ b/sdk/src/golden/golden-policy.ts
@@ -51,6 +51,8 @@ const NO_CJS_SUBPROCESS_REASON: Record<string, string> = {
     'SDK-only structured plan parse (no CJS mirror). Covered in sdk/src/query/plan-task-structure.test.ts.',
   'requirements.extract-from-plans':
     'SDK-only requirements aggregation (no CJS mirror). Covered in sdk/src/query/requirements-extract-from-plans.test.ts.',
+  'commands':
+    'SDK-only registry introspection (no gsd-tools.cjs equivalent — the CJS layer has no self-describing verb). Covered in sdk/src/query/commands-list.test.ts. Closes #3121.',
 };
 
 const READ_HANDLER_ONLY_REASON = (cmd: string) =>
diff --git a/sdk/src/query/command-static-catalog-foundation.ts b/sdk/src/query/command-static-catalog-foundation.ts
index 62fa650e9..794ca9494 100644
--- a/sdk/src/query/command-static-catalog-foundation.ts
+++ b/sdk/src/query/command-static-catalog-foundation.ts
@@ -14,6 +14,7 @@ import { templateFill, templateSelect } from './template.js';
 import { verifySummary, verifyPathExists } from './verify.js';
 import { decisionsParse } from './decisions.js';
 import { checkDecisionCoveragePlan, checkDecisionCoverageVerify } from './check-decision-coverage.js';
+import { commandsList } from './commands-list.js';
 import { checkConfigGates } from './config-gates.js';
 import { checkAutoMode } from './check-auto-mode.js';
 import { checkPhaseReady } from './phase-ready.js';
@@ -95,4 +96,5 @@ export const DECISION_ROUTING_STATIC_CATALOG: ReadonlyArray<readonly [string, Qu
   ['check verification-status', checkVerificationStatus],
   ['check.ship-ready', checkShipReady],
   ['check ship-ready', checkShipReady],
+  ['commands', commandsList],
 ] as const;
diff --git a/sdk/src/query/commands-list.test.ts b/sdk/src/query/commands-list.test.ts
new file mode 100644
index 000000000..d8488177e
--- /dev/null
+++ b/sdk/src/query/commands-list.test.ts
@@ -0,0 +1,36 @@
+import { describe, it, expect } from 'vitest';
+import { commandsList } from './commands-list.js';
+
+// Regression test for bug #3121.
+// The `commands` verb was missing from the SDK native registry.
+// `gsd-sdk query commands` fell back to gsd-tools.cjs which threw
+// "Unknown command: commands".
+describe('commands-list handler (#3121)', () => {
+  it('returns a non-empty sorted JSON array of command strings', async () => {
+    const result = await commandsList([], '/tmp', undefined);
+    expect(result.data).toBeDefined();
+    expect(Array.isArray(result.data)).toBe(true);
+    expect((result.data as string[]).length).toBeGreaterThan(10);
+  });
+
+  it('includes known canonical commands', async () => {
+    const result = await commandsList([], '/tmp', undefined);
+    const cmds = result.data as string[];
+    expect(cmds).toContain('state.begin-phase');
+    expect(cmds).toContain('check.decision-coverage-plan');
+    expect(cmds).toContain('commands');
+  });
+
+  it('is sorted alphabetically', async () => {
+    const result = await commandsList([], '/tmp', undefined);
+    const cmds = result.data as string[];
+    const sorted = [...cmds].sort((a, b) => a.localeCompare(b));
+    expect(cmds).toEqual(sorted);
+  });
+
+  it('args and workstream are ignored (introspection verb)', async () => {
+    const r1 = await commandsList([], '/tmp', undefined);
+    const r2 = await commandsList(['ignored'], '/other', 'ws');
+    expect(r1.data).toEqual(r2.data);
+  });
+});
diff --git a/sdk/src/query/commands-list.ts b/sdk/src/query/commands-list.ts
new file mode 100644
index 000000000..8311f5d5e
--- /dev/null
+++ b/sdk/src/query/commands-list.ts
@@ -0,0 +1,19 @@
+import type { QueryHandler } from './utils.js';
+import { createRegistry } from './index.js';
+
+/**
+ * `commands` — return the full list of registered query command strings.
+ *
+ * Closes #3121: the `commands` verb was referenced in workflow files
+ * (references/workstream-flag.md) but had no native SDK handler, causing
+ * a fallback to gsd-tools.cjs which threw "Unknown command: commands".
+ *
+ * Returns: JSON array of all canonical + alias command strings the SDK
+ * registry accepts, sorted alphabetically. Suitable for discoverability
+ * and for agent auto-complete when constructing `gsd-sdk query` calls.
+ */
+export const commandsList: QueryHandler<string[]> = async (_args, _projectDir) => {
+  const registry = createRegistry();
+  const cmds = registry.commands().sort((a, b) => a.localeCompare(b));
+  return { data: cmds };
+};